Chicken eggs Humans and other Hominidae, hominids have consumed Egg, eggs for millions of years. The most widely consumed eggs are those of fowl, especially chickens. People in Southeast Asia began harvesting chicken eggs for food by 1500 BCE. Eggs of oth ...

are graded by size, for the purpose of sales. The egg shell constitutes 8–9% of the weight of the egg (calculated from data in Table 2, F. H. Harms). Egg scale

Animal welfare

According to Tom Vasey, chair of the British Free Range Producers' Association, laying larger eggs is painful for the hen. He recommends shoppers only to buy eggs of medium or smaller sizes. Professor Christine Nicol of the

University of Bristol The University of Bristol is a public university, public research university in Bristol, England. It received its royal charter in 1909, although it can trace its roots to a Merchant Venturers' school founded in 1595 and University College, Br ...

has stated 'There is no strong evidence of pain in egg-laying hens but it's not unreasonable to think there may be a mismatch in the size of birds and the eggs they produce. We do often spot bloodstains on large eggs.'

United States

The

United States Department of Agriculture The United States Department of Agriculture (USDA) is an executive department of the United States federal government that aims to meet the needs of commercial farming and livestock food production, promotes agricultural trade and producti ...

sizing is based by weight per dozen. The most common U.S. size of chicken egg is 'Large' and is the egg size commonly referred to for recipes. The following egg masses including shell have been calculated on the basis of the USDA sizing per dozen:

Canada

In Canada, modern egg sizes are defined as follows:

Europe

In Europe, modern egg sizes are defined as follows.

Post-Soviet countries

In countries which are members of

Interstate Council for Standardization, Metrology and Certification The Common Economic Space is the goal and the result of the process of economic integration of post-Soviet states envisaged by the Article 7 of the Agreement on the creation the Commonwealth of Independent States signed on 8 December 1991. Accord ...

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

Belarus Belarus, officially the Republic of Belarus, is a landlocked country in Eastern Europe. It is bordered by Russia to the east and northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Belarus spans an a ...

Moldova Moldova, officially the Republic of Moldova, is a Landlocked country, landlocked country in Eastern Europe, with an area of and population of 2.42 million. Moldova is bordered by Romania to the west and Ukraine to the north, east, and south. ...

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a European Kazakhstan, small portion in Eastern Europe. It borders Russia to the Kazakhstan–Russia border, north and west, China to th ...

Azerbaijan Azerbaijan, officially the Republic of Azerbaijan, is a Boundaries between the continents, transcontinental and landlocked country at the boundary of West Asia and Eastern Europe. It is a part of the South Caucasus region and is bounded by ...

Armenia Armenia, officially the Republic of Armenia, is a landlocked country in the Armenian Highlands of West Asia. It is a part of the Caucasus region and is bordered by Turkey to the west, Georgia (country), Georgia to the north and Azerbaijan to ...

Kyrgyzstan Kyrgyzstan, officially the Kyrgyz Republic, is a landlocked country in Central Asia lying in the Tian Shan and Pamir Mountains, Pamir mountain ranges. Bishkek is the Capital city, capital and List of cities in Kyrgyzstan, largest city. Kyrgyz ...

Uzbekistan , image_flag = Flag of Uzbekistan.svg , image_coat = Emblem of Uzbekistan.svg , symbol_type = Emblem of Uzbekistan, Emblem , national_anthem = "State Anthem of Uzbekistan, State Anthem of the Republ ...

Tajikistan Tajikistan, officially the Republic of Tajikistan, is a landlocked country in Central Asia. Dushanbe is the capital city, capital and most populous city. Tajikistan borders Afghanistan to the Afghanistan–Tajikistan border, south, Uzbekistan to ...

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

, and

Turkmenistan Turkmenistan is a landlocked country in Central Asia bordered by Kazakhstan to the northwest, Uzbekistan to the north, east and northeast, Afghanistan to the southeast, Iran to the south and southwest and the Caspian Sea to the west. Ash ...

eggs are sorted into five categories by mass:

Australia

In Australia, the Australian Egg Corporation defines the following sizes in its labeling guide.

New Zealand

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

, sizes are based on the minimum mass per egg. Current sizing introduced in 1973; prior to 1973, sizes were based on the minimum mass per dozen eggs in ounces: 15 (now 4), 18 (now 5), 22 (now 6) and 26 (now 7).

Brazil

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

sizes are based on the mass:

Thailand

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

sizes are based on minimum mass per egg.

Japan

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

, the Japan Egg Association lists the following sizes:

South Africa

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

sizes are based on the mass. :

References

{{Eggs Chicken egg sizes Mechanical standards